Hi I know there has been alot of discussion on over heating crf250r's, but I have a bit of a stumper. My 250r started spewing radiator fluid out the overflow and was getting really hot, riding about 25 mph on open trails after about 5 min. After reading many posts on this site and others we figured a blown head gasket or warped head so we disassembled it, had the cylinder and head checked for warp at a machine shop, there was none, replaced both gaskets, and re-assembled. Bike starts up easy but gets too hot too fast. Our comparison is our 2004 crf250r running at the same time for comparison. I opened up the radiator cap and re-started, and noticed alot of air in the coolant in the 2006 that is overheating where there really isn't any in the 2004 for comparison. So, I believe exhaust air is getting into the coolant and heating / pressurizing it, but the gaskets were just replaced (OEM). I didn't notice any cracks in the head, and there is no coolant leaking from the radiator fins. Also swapped out the radiator cap with the 2004, didn't help. Any suggestions on what to check next?